Ever since Niccolo Machiavelli wrote The Prince, humanity has been concerned with why highly manipulative people, charming on the outside and completely self-centered at the core, exist and how we stop being burned by them. In the last few years an amazing amount of research in the fields of brain scans and genetics has provided an interesting view of what may be a biological basis for antisocial personality disorders. Not only that, but the reason such "successfully sinister" people continue to succeed is that the good-natured part of humanity, the well-meaning naivete that makes us continue to give such people the second chances and others such leeway they need to trample their way to the top, may also have a strong basis in genetics.

As Barbara Oakley explains it, Machiavellian behavior is another word for borderline personality disorder, or a sort of cross between sociopaths, psychopaths and narcissistic personality disorder. Profiled in the book are some of the most successfully sinister people in history: Hitler, Chairman Mao, Stalin, Empress Cixi of China, Slobodan Milosevic, Ceausescu and Roxalena, a member of the harem of Mehmed of the Ottoman Empire. Interspersed throughout are stories about Oakley's experiences with her sister, Carolyn, whose behavior tore a gaping hole in her family until her untimely death at age 54.

The particular combination of forces that make us what and who we are, the formations of our personalities, has been a subject of speculative analysis since Aeschylus began writing plays. Today, studies on personality formation are evolving at a faster pace, thanks to breakthrough techniques in imaging as it relates to genetics. What Oakley is describing, basically, is behavioral genetics, a field that itself is an overlap of genetics, ethology and psychology. Again, this is no recent development: the study of inherited behavior has been around since Francis Galton, a cousin of Charles Darwin's (and the first to coin the term "eugenics") published a book in 1869 (as a result of being gripped by his more famous cousin's work in studies of human population), Hereditary Genius, that examined the role of genetic influences on behavior. Today the field has expanded to include emphasis on molecular genetics (thanks to the Human Genome Project) as a means of analyzing the individual genes that influence behavior.

Many of the recent theories of borderline personality disorder are explained, and in terms someone with no background in science can easily grasp. Oakley's straightforward, clear explanations of various genetic factors are eye-opening, especially concerning the manner in which chemicals such as serotonin, cortisol and dopamine affect the function of our brain. The section detailing the relationship of the hippocampus, the amygdala and the cerebral cortex in the development of morality and cognitive awareness are similarly helpful. All factors included, inheritance does indeed play a major role in how we are able to regulate our moods. While environmental stressors play a strong role in the development of personality, there is strong evidence for a genetic-neurological link that switches certain genes off and on.

Oakley synthesizes a wide range of fields, including the aforementioned behavior genetics, as well as cognitive neuroscience, clinical psychology, history, evolutionary psychology, economics and, of course, her own personal history. All together, this breathtaking range of subjects coalesces into one sweeping -- by no means perfect, but intensely thought-provoking -- theory of how and why malevolent individuals are, with a healthy dose of environmental stressors, biologically formed and how such amoral people rise to the top positions in society.

Oakley emphasizes throughout her book that a great deal of behavioral variation is due to the mutability of environment. She does not focus on the variations of genetic components to the exclusion of environmental factors. The narrative meat, however, is a melding of new research that overlaps between behavior neuroscience and cognitive neuroscience. There is much evidence to suggest that while environmental factors are indeed the triggers that lead to the development of certain personality characteristics, our ability to manage our moods has a strong basis in inheritance. And how is that?

In an (imperfect) nutshell: Genes serve as switches that modulate the mixture of dopamine receptors, cortisol and cerebral cortexes; essentially, these genes produce and modulate the brain's response to neurotransmitters. Serotonin is the active ingredient here. This mixture is impacted by outside input, the aforementioned environmental triggers, to manipulate behavior in a certain direction based on that conditioning. What this means, in a very general way, is that if the right factors combine together into the proper mixture, e.g. a bad home environment combined with an inherited tendency toward unhealthy behavior such as addiction, or even a very bad head injury that messes up the wiring, so to speak, the result is a person who is unable to regulate their moods in a way a person without these disorders can. What you get is Machiavellian behavior, a term Oakley uses as a guide to describe narcissistic personality disorder, borderline personality disorder, sociopathic and psychopathic behavior, conditions that overlap and blend very easily.

Oakley goes out of her way to stress that these conditions are difficult to diagnose because we are still learning about them. No one person really fits a profile exactly: it's much more like a bell curve. Also muddying the waters considerably is the medical field's need to appropriate certain diagnostic terms in order to get insurance for their patients, which leads to patients being labeled with terms that are not exactly the right fit, just so their health coverage is confirmed. There are nuances within nuances, and the path of true understanding is very much in the act of still being created.

How these traits evolve in history and society is how we end up with people like Hitler and Milosevic. Human beings' complicity and cooperativeness exists on a scale, with Machiavellians at one end and the extremely unselfish at the other. Oakley spends considerable time explaining the genetic basis for the altruistic behavior and belief systems that actually allows such malignant narcissists to flourish and end up as leaders who drive companies and countries alike into the ground.

The motivation for much of Oakley's research was her sister Carolyn, a woman whose many psychological problems brought grief to their parents, even to the point where her sister managed to charm her way into their mother's boyfriend's affections. Carolyn's entire life was a trail of turmoil and broken hearts, ending with her death from a heart attack due to either alcoholism or malnourishment, possibly both.

Oakley is working in a very complex and touchy area, directly challenging the romanticism that has, for most of our existence on this planet, surrounded much of our understanding of human behavior. Until Galton published his book, the belief that all human beings are naturally good and that a proper environment is all that's needed to raise a proper person, was paramount in human thinking for centuries. This well-intentioned belief hid a deeper reasoning: that "evil" people are made, not born, and because of that, evil can be controlled. Engineering the social environment would create better people. And if better people can be created, evil can be eliminated. But studies by the ton dispute that widely held belief. It may be difficult to believe that a strong genetic component can be a huge factor in the creation of the successfully sinister, but neuroscience is beginning to give us some interesting insight and the results of these studies need to be communicated to the public in general. As Oakley states while describing a disagreement with a psychotherapist, parents of children who are psychopathic, might be very relived to know that it wasn't their parenting style so much as an unlucky shake of the genetic dice that made their children what they are.

It is important to approach this book not as an academic volume, but as a sort of jigsaw puzzle with many pieces missing, simply because the research needed for all the areas discussed is still a work in progress. It is Oakley's stated aim that this book not provide answers as much as a window into the research that already exists, and help propel further research and discussion into these vital areas, moving the field forward into a greater understanding than our current black-and-white thinking permits.

Oakley not only outlines a wonderfully concise explanation of just what Machiavellians truly are and how they probably tick, she also seems to have found, by the end of the book, a way to come to terms with her sister's life and rather sad death. This makes Evil Genes a rather personal exploration, adding a very human touch to a book that could easily have been coldly factual.

As I was reading this book I did what I suspect many people who have read this book have done: I began to "recognize" people I had known who fit the profile, some I had known personally, some from the accounts of others. We have all, in fact, had experiences with such people, perhaps not always with the big-time sociopaths such as Mao and Hitler but with the "below the radar" antisocial people, the petty tyrants like the boss from hell, the insane next-door neighbor, the relative who seems to redefine the term "black sheep" or the friends and lovers who cause turmoil and heartbreak with their seeming addiction to creating dark melodrama. In addition to retroactively filling in the blanks about some of the more, erm, colorful characters you have probably known (unless you live on an island, it is, in all practicality, statistically impossible for you not to have run into a Machiavellian individual), you may end up with a better idea of how to profile those individuals who seem cooperative and charming but are really out for themselves.